Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1887-05-08
ASTRONOMICAL.
PROFESSOR STONE ON LARGE AND
SMALL TELESCOPES.
Their Relative Value What 10 TO be
Expected Of the Lick
Telescope.
IRASpYR McCoRMrcx OBSERVATORY,
UNIVERSITY OF VIRGINIA,
Nav 2. 1897.

Lick telescope of California have
already reached their destination, and
arc awaiting their gigantic tube and it's
mounting, which are nearing compile
ton. This telescope will be so much
larger than any refractor hitherto con-
structcd, and the expectations in regard
to the grand results 10 be obtained from
its use have been raised so high-gene-
rally so unreasonably high-that it may
be OF intccst TO consider what may be
reasonably hoped for.
in the frst place, as suggested 10y
Professor Hall in his address at the
opening Of this observatory, call the
obvious and striking discoveries of
astronomy have been made long since. y
Moreover, the mere detection of celes-
tial objects docs not always require the
highest order Of ability nor the most
powerful telescope. For instance, an
astronomer would never think of wasting
his energies by the use Of q powerful
telescope in searching for comets. Such
course would be good advertising
dodge and give temporary 6ctat, but
comet. seeking, while useful and need
ing perseverance for its successful pur-
suit, requires only the most limited
instrumental means; in fact, n
small telescope is much better for
the purpose than large one.
The largest telescopes should be reserved
for such work as can only be accom-.
plished by the use of such instruments;
still the temptation TO bid for 6ctdt is
often great in view of too-frequently-
depleted Golfers and the possibility of
thereby gaining the attention of some
one who may be able and willing to
supply the means Of carrying on work
of greater and more permanent value.
II is to be hoped that the great Lick
telescope will not be devoted to an at
tempt 10 accomplish results which have
no other scientific value than the her
aiding OF the names of their authors in
the public press.
Valuable observations can still be
made even with the naked eye, and
for many purposes the accuracy attain
ed by the use of telescopes of moderate
power is ample. Although undoubted-
" in most eases single observation
made with q large instrument would be
better than one made with q smaller
one. still this small difference is often
far out-weighed by the greater time
and energy required in the manipuls-
ton of the former. There Is, however,
a large amount of work which re-
CURES for its successful accomplish
ment the most powerful instrumental
means obtainable, %, for instance. IN
themicromotric0l measurements OF very
close double stars and Of the fainter
satellites Of the outer planets and OBJ
servations of positions of nebule.
A good illustration of the value OF a
LARGE telescope in double-star work is
found IN the history of Mr.. 5. W.
Burnham's successes. Mr.. Burnham
first became distinguished as double
star observer by his remarkable series
of discoveries commenced about twenty
wears AGO: do not remember the exact
wear. but ! think it was in 1853. Until
July, 1877. most of his discoveries OF
new double stars were made with a
Telescope having an aperture OF only
six inches in diameter. Many of these
objects were Quite close and difficult,
and their detection with so small an in
strument naturally excited the admira'
ton of every one who knew of his work.
During the next four years, however,
from the summer of 1877 to that of
1881. aided by the use of the nagniti-
cent refractors of the Dearborn obser-
yatorv. Chicago, and the Washburn
observatory, Madison, Mr.. Burnham,
besides discovering during that time
more new double stars than he had de-
tected during the eight or nine years
preceding, made a series Of some $500
micrometrical measurements. leavlnga
record Of scientific Industry almost or
unite unsurpassed in the annals OF
practical astronomy 1t is safe to say,
If scientific work can be so measured,
that on the average each of Mr.. Burn
hams four wears work with large In
struments was worth at least six times
the average OF his previous years with
small one.
Another illustration of the difference
in value between a small telescope and
a large one may be found by an ex-
animation of the comparative accu-
racv of micrometrical measurements OF
double stars made with telescopes OF
different sizes. Probably i'll no other
country have so many double-star
observations been made as i'll our own.
A comparison of these observations
show that while in the case OF
wide doubles observations made
at Cincinnati with al 11-inch re-
tractor give results comparable IN
accuracy with those made with the
great refractors at Madison, Chicago,
and Washington still, in the case Of
very close objects, the difference is so
Great as to show that measurements
ade with smaller instruments are
q most useless. This statement is espe-
cially important in view of the fact that
the proportion of objects having or6ltal
motion is much greater among close
doubles than among wide ones, and
consequently close objects are more
deserving OF careful observation.
Professor Hall, the distinguished as
tronomer Of the Washington observa-
tory, is best known, so far as the gene
raj public is concerned, by the discoy-
erv Of the satellites of Mars. The de-
lection Of these faint objects was the
direct result of the employment of a
powerful telescope in the hands OF a
trained astronomer. The fact that
these objects have been since seen with
greatly inferior instruments is now
and then cited to show that the dis
coyery deserved after all but little
credit. Such a conclusion can only
he reached by one who is unfamiliar
with the practical difficulties Of astros
nomical discovery. 1T is always far
easier TO see an object when we know
exactly where TO look and what to look
for than for the first time to detect its
existence. II is generally no easy thing
to make an original discovery of value
in astronomy or in any other depart
ment of science. 1t is, however,
easy TO speak Of discoveries made
by others and which We ourselves
have missed, as simple and obvious.
Professor Hall, in an interesting ac-
count OF his discovery. after relating
how the idea occurred to him of
making careful search for a satellite
OF Mars, says: "An examination of
the literature of the planet showed,
IIxx1xop otrnb a rracc as ahoor~att